Obama to address nation on Syria

ST. PETERSBURG, Russia - President Barack Obama acknowledged that he had a "hard sell" with Congress and announced that he would deliver a televised address to the nation from the White House on Tuesday evening.

"Failing to respond to this breach of this international norm would send a signal to rogue nations, authoritarian regimes and terrorist organizations that they can use WMD and not pay a consequence," he told a news conference, using initials for weapons of mass destruction. "And that's not a world we want to live in."

Speaking at the end of a two-day economic conference overshadowed by his call to strike Syria, Obama said he'd "make the best case that I can" to a nation that polls show is widely opposed to military intervention.

"There are times where we have to make hard choices if we're going to stand up for the things that we care about," the president said. "And I believe that this is one of those times."

He cast the regime's "brazen use" of chemical weapons and the deaths of hundreds of children as a violation of international norms and said failure to act would empower other "rogue nations, authoritarian regimes and terrorist organizations" to develop and use weapons of mass destruction.